A cavity is a hole in the tooth that develops as a result of tooth decay, which breaks down tooth enamel and destroys tooth structure. When sugars and starches are left on the teeth, plaque forms and combines with bacteria, producing acids that eat away at tooth enamel and cause decay.

There are a number of measures a person can take to avoid the decay that leads to cavities. The most important factor to the prevention of cavities is maintaining a strong oral hygiene routine. Brushing at least twice a day, daily flossing, and twice yearly professional dental cleanings are crucial to the removal of plaque, which can lead to cavities if left unaddressed. A healthy diet is also important to the prevention of dental cavities: foods that are high in sugar and carbonated beverages should be limited.

A dental filling is often used to fill the hole left in a tooth by dental decay or a cavity. However, if the cavity has gone untreated long enough that it has reached the tooth root, a root canal procedure will most likely be needed to save the tooth.